Photographic dry copying process with a neutrostyryl dye

ABSTRACT

A PROCESS FOR THE PRODUCTION OF COPIES BY IMAGEWISE EXPOSURE OF A LIGHT SENSITIVE LAYER WHICH CONTAINS A SENSITIZER AND AN IMAGE PRODUCING COMPOUND WHICH IS TRANSFERABLE TO AN IMAGE RECEIVING LAYER, THE IMAGE PRODUCING COMPOUND IN THE EXPOSED AREAS BEING CONVERTED INTO A NONTRANSFERABLE COMPOUND CONTACTING THE EXPOSED LAYER WITH AN IMAGE RECEIVING LAYER WHICH CONTAINS COMPOUNDS WHICH REACT WITH THE IMAGE PRODUCING COMPOUND TO FORM COLORED COMPOUNDS, AND HEATING OF THE LAYERS WHICH ARE IN CONTACT WITH EACH OTHER TO A TEMPERATURE AT WHICH THE IMAGE PRODUCING COMPOUND IN THE UNEXPOSED AREAS OF THE LIGHT SENSITIVE LAYER IS TRANSFERRED TO THE IMAGE RECEIVING LAYER. IN THE PROCESS IS USED A LIGHT SENSITIVE LAYER WHICH CONTAINS AS LIGHT SENSITIVE COMPOUNDS, SELECTED NEUTROSTYRYL DYES, AS IMAGE PRODUCING TRANSFERABLE COMPOUND, A REDUCING AGENT WHICH IS TRANSFERABLE AT A TEMPERATURE OF BETWEEN 80*C. AND 200*C9 AND WHICH IS CONVERTED INTO NON-VOLATILE REACTION PRODUCTS WHEN THE MATERIAL IS EXPOSED.

United States Patent O 3,764,321 PHOTOGRAPHIC DRY COPYING PROCESS WITH A NEUTROSTYRYL DYE Helmut Kampfer and Hans Ohlschlager, Cologne, and Anita von Konig, Leverkusen, Germany, assignors to Agfa-Gevaert Aktiengesellschaft, Leverkusen, Germany No Drawing. Filed Aug. 25, 1971, Ser. No. 174,927

Claims priority, application Germany, Aug. 28, 1970, P 20 42 663.5 Int. Cl. G03c 5/54 US. C]. 96-29 D 34 Claims ABSTRACT OF THE DISCLOSURE A process for the production of copies by imagewise exposure of a light sensitive layer which contains a sensitizer and an image producing compound which is transferable to an image receiving layer, the image producing compound in the exposed areas being converted into a nontransferable compound contacting the exposed layer with an image receiving layer which contains compounds which react with the image producing compound to form colored compounds, and heating of the layers which are in contact with each other to a temperature at which the image producing compound in the unexposed areas of the light sensitive layer is transferred to the image receiving layer. In the process is used a light sensitive layer which contains as light sensitive compounds, selected neutrostyryl dyes, as image producing transferable compound, a reducing agent which is transferable at a temperature of between 80 C. and 200 C. and which is converted into non-volatile reaction products when the material is exposed.

The invention relates to a photographic dry copying process and to a light-sensitive material for carrying out this process.

Dry photographic processes for producing copies of an original are already ynown. The materials used are mainly layers which are sensitive to light or heat. These layers are exposed imagewise to light or heat which initiates a color producing reaction by which the image is formed.

The known light-sensitive materials of the type mentioned above which can be used for producing negative copies have, however, numerous disadvantages. Their sensitivity to light is insufficient, especially in the visible region of the spectrum, with the result that the times required for copying are too long and the reproduction of colored originals gives rise to difliculties.

Moreover, the produced images are still sensitive to light and stabilization against daylight can generally only be achieved by a very complicated after-treatment Processes for the production of copies by imagewise exposure of a light-sensitive layer which contains a lightsensitive compound and an image-producing compound which can be transferred to an image-receiving layer are known. In such a process, the image-producing compound in the exposed areas is converted into a non-transferable compound, the exposed layer is brought into contact with an image-receiving layer which contains compounds which react with the image-producing compound to form colored compounds, and the layers which are in contact with each other are heated to a temperature at which the imageproducing compound in the unexposed areas of the lightsensitive layer is transferred to the image-receiving layer.

These processes include e.g. the so-called heat development processes in which light-sensitive materials comprising a silver halide emulsion layer are used which contain a photographic developer substance. After exposure, the material is developed by heating it in contact with an image-receiving layer which contains substances which react with the developer substance to form dyes. The de- 3,764,321 Patented Oct. 9, 1973 veloper substance in the unexposed areas of the lightsensitive layer is transferred by heat into the imagereceiving layer, so that a colored image is formed in these areas of the receiving layer.

One disadvantage of these known heat development or developer-sublimation processes is the insufiicient stability in storage of the silver halide emulsion layers which contain developer substances, this instability being due to the presence in these layers of substances which increase the residual moisture of the layers, e.g. salts which form hydrates, or glycols, and to the increased sensitivity to oxidation of most developer substances in these unhardened or only slightly hardened emulsion layers which have a high residual moisture content.

A process which belongs to this type of copying process is described in US. patent specification No. 3,094,417. In this process, light-sensitive layers which contain a transferable compound and a dye are used. On exposure to light, the transferable compound (4-methoxy-l-naphthol) is converted into a nontransferable product. This compound is transferred from the unexposed areas into an image-receiving layer by subsequent heating, and in this image-receiving layer it reacts with a silver salt (silver behenate) to produce a colored positive image.

The last mentioned process has the disadvantage that the sensitivity of the layers is relatively low and the keeping quality of the material is limited.

It is the object of the invention to provide photographic dry copying processes and light-sensitive materials suitable for these processes, which materials have sufficient sensitivity to light and stability and contain dyes which render the material sensitive to the required spectral range and enable multicolored and black and white images to be produced.

We now have found a process for the production of copies by irnagewise exposure of a light-sensitive layer which contains at least one sensitizer and one image-producing compound which can be transferred into an imagereceiving layer, the image-producing compound in the exposed areas being converted into a non-transferable compound, and the exposed layer is brought into contact with an image-receiving layer containing compounds which react with the image-producing compound to form colored compounds, and the layers in contact with each other are heated to a temperature at which the image-producing compound from the unexposed areas of the light-sensitive layer is transferred to the image-receiving layer, in which process there is used a light-sensitive layer which contains as sensitizers neutrostyryl dyes of the following general formula, and which contains, as image-producing, transferable compound, a reducing agent which is transferable at a temperature of between and 200 C. and which is converted into non-volatile reaction products on exposure of the material wherein R and R may also, taken together, represent the ring members required to complete an isocyclic or heteroseries, or the ketomethylene compounds characterized by the following structural formulae:

The heterocyclic rings and aryl groups may be substituted in any way, e.g. with additional alkyl groups which preferably contain up to 3 carbon atoms, such as methyl or ethyl, or halogen such as chlorine, bromine or iodine, or the trifiuoromethyl group, hydroxyl, or alkoxy, preferably containing up to 3 carbon atoms such as methoxy or ethoxy, alkoxycarbonyl, hydroxyalkyl, alkylthio, aryl such as phenyl, or aralkyl such as benzyl, amino, substituted amino and the like.

The following are examples of suitable compounds:

(1) n m-on=on-oo-on=ong n -on=on-on =on-on=on@ -crnooon Hooo-om- Q o 0 1 l,

on =s i ll |N O Q n N o O2NT on: :s r It (l2) 0 (EH5 u N o CH=CHCH= =s 0 on=on-cn=on cn s H I I N OWN- 2 .9

The dyes according to the invention are easily obtained by condensation of ketomethylene compounds with the corresponding aldehydes in solvents such as alcohol, pyridine or glacial acetic acid, if desired with the addition of a base such as triethylamine or piperidine.

The preparation of dyes 7 and 26 will be described in detail below.

Dye 7 2.5 n11. of 50% sodium hydroxide solution are added to a solution of 4.0 g. of o-hydroxy-cinnamic aldehyde-O- acetic acid and 1.0 g. of cyclohexanone in 50 ml. of alcohol. The mixture is left to stand for 30 minutes at room temperature and is then acidified with dilute hydrochloric acid. The dye is removed by suction filtration and recrystallized from chloroform/methanol. 2.4 g., M.P.: 264 to 266 C. (decomposition).

Dye 26 2.0 g. of 1,3-diethyl-thiobarbituric acid are heated on a steam bath with 1.7 g. of 4-dimethylamino-cinnamic aldehyde in 50 m1. of alcohol for 30 minutes. The dye is filtered 01f after cooling and is recrystallized from chloroform/methanol. 3.3 g., M.P.: 212-214 C.

The image-producing compounds must meet the following conditions: i

(1) They must react in the presence of the sensitizers defined above upon exposure to form non-transferable reaction products.

(2) They must be transferable at temperatures of between 80 and 200 C. to the image-receiving layer.

(3) They must be capable of reacting with the compounds of the image-receiving layer to form colored reaction products.

The following reducing agents, for example are particularly suitable:

(1) Phenols and naphthols, especially benzenes and naphthalenes which contain at least two aromatic hydroxyl groups which may be partly etherified or those which are substituted with a hydroxyl group and an amino group or a substituted amino group, the substitution being in the paraor ortho-position in the case of benzene derivatives, e.g. the compounds listed in Table 1.

TABLE 1 1-hydroxy-4-methoxynaphthalene 1-hydroxy-4-ethoxynaphthalene 1-hydroxy-2-methyl-4-methoxynaphthalene 4,4-dimethoxynaphthalene-1,1'-dihydroxy-2,2'-binaphthyl 1,4-dihydroxynaphthalene l-hydroxy-4-aminonaphthalene 1,2,3-trihydroxy-5-acetyl benzene methyl-3,4,5-trihydoxy benzoate ethyl-3,4,5-trihydroxy benzoate 1,2,3,4-tetrahydro-8-hydroxyquinoline 1-[Z-methylsulphonamidoethyl]-l,2,3,4-tetrahydro- 6-hydroxyquinoline ,s 4-methylaminophenol s-isopropylidene aminoplls ol 4-aminophenol 4-hydroxyanilino methane sulfonic acid 4-hydroxy-3-methylanilino methane phosphonic acid 1-hydroxy-4-propoxynaphthalene Reference may also be made to the aminophenol de velopers described in German patent specifications Nos. 1,159,758; 1,200,679; 1,203,129 and 1,203,605.

(2) Pyrazolidone-(3) derivatives of the following formula:

n R JC=O R N-R wherein R represents a hydrogen atom, an alkyl or aryl group which may be substituted, for example with lower alkyl or alkoxy groups or halogen,

R represents a hydrogen atom, and

R R 11 and R represent hydrogen, alkyl, aryl or a substituted alkyl or aryl group.

The compounds listed in the following table have been found to be suitable.

TABLE 2 The compounds shown above may be prepared by the methods described in British patent specification Nos. 679,677 and 679,678, the phenimines which may be obtained by reacting acrylonitrile derivatives with the corresponding hydrazine compounds being saponified to 3-pyrazolidones.

Furthermore, 3-pyrazo1idones may be prepared by the process described in British patent specification No. 703,669, the end products being obtained by direct condensation of esters of acrylic acid or derivatives thereof with hydrazines. This process is especially suitable for reactions with hydrazine itself. The resulting 3-pyrazolidones of oily consistency can be obtained as crystalline compounds by converting them into salts, e.g. hydrochlo rides, sulfates or 1,5-naphthalene disulfonates. The preparation of 4,4-dia1kyl-3-pyrazolidones has been described in US. patent specification No. 2,772,282. In this process, 2,2-dialkyl-B-chloropropionic acid chlorides are reacted with hydrazines. e

3-pyrazolidones may be used as free, bases or in the form of their salts.

(3) Pyrazolin-S-one derivatives: The pyrazolin-S-one derivatives are preferably those which contain at least one hydrogen in the 4-position of a 4-aminophe'nylamino group.

Pyrazolin-S-one compounds of the following formula are preferred:

10 (7) amino which may be substituted, e.g. with alkyl, preferably with alkyl having up to 3 carbon atoms, (8)

alkoxycarbonyl containing up to carbon atoms; I 1 R is 1) a hydrogen atom, (2) a saturated or olefinically l 5 unsaturated aliphatic group which preferably contains N up to 6 carbon atoms and which may be substituted, N e.g. with phenyl as in the case of benzyl or phenylethyl groups, with halogen such as chlorine or bromine, or with nitrile, alkoxy, alkoxycarbonyl or anilinocarbonyl, R 1s (l) a hydrogen atom, (2) a saturated or olefinically (3) an aryl group, especially a group f the phenyl Unsaturated ahphatlc p, Preferably eontelmng P series, the aryl ring being itself substituted if desired, to 6 Carbon m Whleh group y e sueslltutedy e.g. with alkyl or alkoxy which preferably contains up Wlth p y as In the benzyl group, nltnlegmups, to 3 carbon atoms, nitro or nitrile, (4) amino which h g fluorine, Wlth afmne whlch may may be substituted, e.g. with an alkyl which preferably itself be Substituted, alkylated ammo groups, P contains up to 3 carbon atoms, cycloalkyl, phenyl or cially i lkyl mi the alkylgfeupsin the amino group acyl, especially acyl groups of short chain aliphatic Preferably Containing p to 3 Carbon atoms, an carboxylic acids, (5) alkoxy which preferably contains aryl group, especially a group of the phenyl series, and up to 3 carbon atoms; the aryl ring may itself be substituted, e.g. with alkyl 15 is a hydrogen atom a 4 i 1 i group or alkoxy preferably containing up to 3 carbon atoms, m 4 dialkylaminophenylamino group nitro, halogen such as fluorine, chlorine or bromine, 13 and 14 may also together represent h i members amino or su s d amine g p alkylated required to complete a S-membered or 6-membered amino groups, (4) a heterocyclic group, e.g. benzocarbocyclic or heterocyclic i thiazolyl or (5) cycloalkyl such as cyclohexyl 0r cyclopentyl; Suitable compounds are shown 1n the following table.

RI Rli TABLE 3 i f igj R12 R13 u p Y m-Chlorophenyl- 2,5-dichlorophenyl 3-nitrophenyl 4-nitrophenyl. C 6H5 l-phenyleth l C sH5 2-diethylaminoethy1-. CH 2,4,6-triehlorophenyl. 2,4,5-trichlorophenyl. 2cyan0ethyl CflH5 1;), 5igimethylphenyh CsH 5 3-nitrophenyl C 3 C 3. -dimethyl-4-ll-diethylaminophenylamino]-pyrazolin- 5one. 1-pheny1-3,4-dimethyl-4-[4-diethylaminophenylamjn0]-pyrazo1in-5-one R is (l) a hydrogen atom, (2) a saturated or olefinically unsaturated aliphatic group which preferably contains up to 6 carbon atoms and which may itself carry substituents, e.g. phenyl as in the case of a benzyl or phenylethyl group, halogen such as fluorine, chlorine or bromine, alkoxycarbonyl, hydroxyl or alkoxy, (3) an aryl group, especially a group of the phenyl series, the aryl ring being substituted if desired, e.g. with alkyl or alkoxy preferably containing up to 3 carbon atoms or with nitro or halogen such as chlorine or bromine, (4) a heterocyclic group, e.g. pyridyl, (5) a cycloalkyl group such as cyclohexyl or cyclopentyl, (6) a hydroxyl group which may be etherified, especially with short The pyrazolin-S-one derivatives are prepared by methods known from the literature. Reference may be made e.g. to the monograph by R. H. and Wiley Pyraz olones, Pyrazolidones and Derivatives (1964) and to German patent specification No. 1,155,675.

The light-sensitive layers contain at least one sensitizer in quantities of 10 to 300 mg./m. and one or more image-producing compounds in quantities of 0.02 to 0.5 g./m. This range of concentration has been found to be suitable, although quantities outside this range may, of course, be used. The concentration depends mainly on the requirements of the particular reproduction process.

Particularly suitable combinations of sensitizers and chain aliphatic radicals containing up to 3 carbon atoms, image-producing reducing agents can be found by simple tests. Suitable tests for this purpose will be described hereinafter. The choice of solvent and of the binding agent used for preparing the light-sensitive layer is also important for obtaining optimum results. Particularly suitable combinations of components for any particular purpose can be determined by the usual experiments commonly known in the art.

For preparing the light-sensitive layer, sensitizers and image-producing compounds may be suspended or dissolved in solvents and mixed with a binding agent and applied in this form to the layer support.

The usual natural or synthetic film-forming polymers are suitable as binding agents for the light-sensitive layer, e.g. proteins, especially gelatin, cellulose derivatives, especially cellulose ethers, cellulose esters or carboxymethyl cellulose, alginic acid and its derivatives, starch ether or gallactomannane, polyvinyl alcohol, polyvinyl pyrrolidone, polyvinyl chloride, copolymers of vinyl chloride and vinyl acetate, polyvinyl acetate or completely or partly saponified polyvinyl acetate, or copolymers of vinyl acetate, for example with olefines such as ethylene or propylene and copolymers of monomers of acrylicor methacrylic acid or derivatives thereof such as esters, amides or nitriles, etc. The light-sensitive layers may be used as self-supporting layers or applied to a support. Suitable supports are e.g. paper, especially baryta-coated paper and cellulose esters, e.g. cellulose triacetate, polyesters, especially those based on ethylene terephthalate, glass etc.

The image receiving material advantageously consists of an image receiving layer applied to a suitable support. Substantially the same substances as those described above for the light-sensitive material are suitable as binding agent for the image receiving layer or as the layer support.

When choosing a binder for the light-sensitive layer and the image receiving layer, care should be taken to ensure that the layers Will not stick at elevated temperature. These difi'iculties, however, are well known from other transfer processes, e.g. the silver salt diffusion process or heat development processes, and can easily be solved by making use of the experience gained in these known fields.

The image receiving layer contains compounds which should be insensitive, or as restricted as possible in their sensitivity, to visible light under the conditions of the process of the invention, and which react with the transferred image producing compounds to form colored products. Numerous compounds have been found suitable for this purpose. Chemically, these compounds belong to a wide variety of classes so that their systematic chemical classification is not possible. However, suitable compounds or suitable combinations of an image producing compound arranged in the light-sensitive layer and of the reactant for the image-forming reaction in the image receiving layer can be sufiiciently clearly defined by simple laboratory tests customarily employed in the art. Thus, for example, the two reactants must react when briefly heated for a few seconds to a temperature of between about 80 and 200 C. to form a stable dye. A second test must then be carried out to choose suitable image producing compounds. The purpose of this test is to show whether the image producing compound will react sufficiently rapidly in the presence of the sensitizer on exposure to light, so that, when the mixture is heated after it has been exposed, it will not produce a colored compound with the reactant in the image receiving layer.

The following classes of compounds are examples of suitable compounds in the image receiving layer for reaction with the image transferred from the light-sensitive layer.

(1) Heavy metal compounds, especially compounds of metals of Groups Illa to Va and Groups Ib, IIb, VII) VIII), and VIII of the Periodic System of Elements, e.g. compounds of the following heavy metals: cadmium,

mercury, iron, cobalt, nickel, copper, silver, gold, bismuth or thallium. Salts of these metals with long chained aliphatic, carboxylic acids are especially suitable, e.g. nickel stearate, cobalt palmitate, iron stearate, and the addition compound of bismuth nitrate with amines such as triethanolamine. It is found to be especially suitable to use silver compounds which are substantially insensitive to light under the conditions of the copying process according to the invention, e.g. the silver salts described in U.S. Pat. No. 3,330,663 i.e. silver salts of aliphatic carboxylic acids having a thioether group or silver salts of long-chained fatty acids such as silver behenate, silver palmitate or silver stearate, etc. When the above-mentioned heavy metal compounds are used, brown to black copies are obtained. The image consists of the particular metal and/or a reaction product of the transferred image producing compound.

(2) The image-receiving layer may also contain oxidizing agents and dye components which undergo an imagewise reaction of oxidative coupling with the transferred image-producing compound to yield dyes, e.g. compounds which in their oxidized form produce colored coupling products when reacted under oxidizing conditions with e.g. pyrazolin-S-one compounds. Suitable reactants are e.g. oxidation products of p-phenylene diamines or their derivatives which form azomethine dyes with the pyrazolin-S-one compounds, as known from conventional color photography.

(3) Diazonium salts which react with the transferred reducing agents, eg the aminophenols, aminonaphthols or pyrazolin-S-one compounds, to form a colored product. In principle, this reaction corresponds to the reaction employed in the known photographic diazotype process.

(4) Leucophthalocyanines are also suitable reactants for the reaction which produces the image dye. Leucophthalocyanines which have not or could not be prepared from finished phthalocyanines are known as phthalocyanine precursors. This term is used, for example, in the article by B. R. A. Brooks, J. G. Burt, B. F. Skiles and M. S. Whelen, J. Org. Chem. 24, p. 383 (1959). In the relevant chapter in Ullmanns Encylopadie der Technischen Chemie, 3rd edition, vol. 13, the term phthalocyano-rnetal complexes is used for the same type of materials for which in the present context the term leucophthalocyanines is used. The last mentioned expression is explained e.g. in U.S. Pat. No. 2,772,285. Although it refers there only to leuco copper phthalocyanine, it is also applicable analogously to the corresponding complexes with other metals which form phthalocyanines. Leucophthalocyanines according to this definition are colorless or only slightly colored products in which the phthalocyanine structure is already completely formed, and which can be converted into phthalocyanines by a reduction process. In this reduction process, constituents which the leucophthalocyanine molecule contains in addition to phthalocyanine may also be split oil. Such leucophthalooyanines may be prepared e.g. by first preparing a phthalocyanine, e.g. a phthalocyanine which is free from metal or CuPc (Pc=phthalocyanine), NiPc, CoPc, or ZnPc and then treating the phthalocyanine with additional ligands under oxidizing conditions, or by heating a reaction mixture which is in itself suitable for the preparation of a phthalocyanine to a temperature slightly below that required for the preparation of the phthalocyanine, or by carrying out the reaction without the reduction potential required for formation of the phthalocyanine.

Leucophthalocyanines which contain metal are more suitable for this reaction because those which are free from metal are relatively unstable. The highly stable and only slightly colored leuco cobalt phthalocyanines are especially suitable. Especially to be mentioned are the leuco cobalt phthalocyanines which are described in Angewandte Chemie, 68, p. (1956), e.g. the phthalocyanine cobalt ethylene diamine complex. Instead of ethyl ene diamine, other diamines or polyamines may also be used as ligands, for example propylene diamine-(1,2), and -(1,3), monoethylpropylene diamine-(1,3), hydroxyethylethylene diamine, N methyl-N-fl-hydroxyethylpropylenediamine, N,N' diethylethylene diamine, N,N-di- (fl-aminoethyl) ethylene diamine, N,N'-di-(/3-aminoethyl)-ethylene diamine or N,N di [fi-(B-aminoethyl} amine or also monoamines such as 3-(2-ethylhexyloxy)- propylamine-(l) or stearylamine. The solubility properties of the leuco-Co-Pc depend on the type of amine used in the molecule.

In another embodiment of the process according to the invention, the reactants in the image-receiving layer for a reaction to produce dyes can be eliminated altogether. This applies e.g. to image--producing compounds for example phenols or naphthols, which yield colored compounds spontaneously when heated or in the presence of sufficient atmospheric oxygen. In that case, plain, uncoated paper may be used as image-receiving material.

In addition to the image forming reactants, the image receiving layers may also contain other additives which advantageously alfect the color tone, contrast and stability, etc. of the copy. Image receiving layers of this type are already known and have been described e.g. in US. Pat. No. 3,335,006 and Belgian Pat. No. 609,057.

The image-receiving layers may also contain white pigments such as zinc oxide, silicon dioxide or titanium dioxide as fillers, to improve the whites and to control the tendency of the layers to stick, and they may also contain terpene resins and organic acids to improve the stability in storage. Image-receiving layers of this type have been described in US. patent specifications Nos. 3,074,- 809 and 3,107,174. The color tone of the images obtained can be adjusted e.g. with compounds of the 1-(2H)-phthalazinone series. Toners of this type have been described in US. patent specification Nos. 3,080,254 and 3,446,648. Additives which accelerate the reduction reaction in the image receiving layer have also been found advantageous. Suitable compounds for this purpose are e.g. sterically hindered phenols, e.g. 2,6-di-tert-butyl-p-cresol. Compounds of this type have been described in US. patent specification No. 3,218,166. The image tone and density of the image can also be improved with certain salts, e.g. copper-II stearate. Such image intensifying compounds which contain metal ions and their application have been described in German Auslegeschrift No. 1,572,209.

The light-sensitive layers according to the invention may be exposed with the usual sources of light used in reproduction work, such as mercury lamps, iodine quartz lamps or incandescent lamps. The spectral sensitivity of the light-sensitive material depends on the nature of the dye used or of the combination of dye and reducing image producing compound.

Exposure may either contact exposure, optical exposure or reflection exposure.

Transfer of the image-producing compounds from the unexposed areas of the light-sensitive layers to the imagereceiving layer is carried out at temperature of between 80 and 200 C. Heating may be carried at e.g. by passing the exposed light-sensitive layer in contact with the imagereceiving layer over hot plates or rollers or by irradiation with infra-red light. The most advantageous temperature and heating time depends, of course, on the nature of the image-producing compound and can easily be determined by a few simple tests.

The material according to the invention may also be modified in that the image-receiving layer and the lightsensitive layer may both be applied to the same support. In this case, it is necessary to use a transparent layer support on which there is first applied the image-receiving layer, e.g. a layer which contains silver behenate dispersed in a copolymer of styrene and isobutylene, and on this image-receiving layer there is applied the light-sensitive layer, e.g. an ethyl cellulose layer containing the sensitizer and reducing agent.

By combining the material used according to the invention with dyes which can be reduced by light, e.g. those mentioned in US. patent specification No. 3,094,417, e.g. erythrosine, the sensitivity of these light-sensitive layers can be advantageously increased and/or extended to other spectral regions, which will depend on the absorption of the compounds according to the invention.

EXAMPLE 1 Light sensitive material The following casting solution is applied to a layer support of glassine paper:

30 mg. of Dye. No. 33,

50 mg. of 1-hydroxy-4-methoxynaphthalene,

2.5 g. of ethyl cellulose as a 5% solution in butanone-2 150 ml. of butanone-2.

The layer is dried in the usual manner.

The image-receiving material is prepared by grinding the following components in a ball mill for 6 hours:

and applying the mixture on paper and drying it. When dry, the layer contains about 0.2 g. of silver per m? in the form of silver behenate.

Processing The light-sensitive material is exposed behind a /2 step wedge for 5 minutes to a 1000 watt iodine quartz lamp from a distance of 30 cm.

The exposed layer is then brought into contact with the image-receiving layer and heated for 10 seconds to a temperature of C. or treated in a commercial heat development apparatus. Instead of Dye No. 33, the dyes listed in Table 4 below may be used.

TABLE 4 Dye No.2

Steps /2 Without TABLE 4-Continued Light-sensitive material The following casting solution is applied to a layer support of glassine paper:

30 mg. of dye no. 32,

50 mg. of l-hydroxy-4-methoxynaphthalene, 2.5 g. of ethyl cellulose, and

150 ml. of ethyl acetate.

The layer is dried in the usual manner.

Processing The light-sensitive material is exposed through a positive transparent original copy to a normal 1000 watt incandescent lamp (tungsten filament) at a distance of 5 to cm. for 30 seconds.

Instead of a transparent copy, a text printed on ordinary paper may be used as original. Exposure must be in this case to reflected light and times of between and 25 seconds are required for this under otherwise the same conditions.

The exposed layer is then brought into contact with the image-receiving layer described in Example 1 and the layers are heated to a temperature of 125 C. to 140 C. for 5 to seconds or treated in a commercial heat development apparatus.

A sharp, positive black copy of the original is obtained.

Instead of dye no. 32 and instead of the image-producing compounds described above, other combinations may be used. The results are summarized in Table 5 below.

Instead of silver behenate which is used here in the image-receiving layer, other silver compounds may be used, e.g. silver stearate or silver salts of octadecylmercaptoacetic acid, 2-octadecylmercapto-S-carboxymethylmercapto-1,3,4-thiadiazole (as described in US. patent specification No. 3,330,663), etc. The choice of suitable compounds dependsron the purposev for which they are to be used and the required color of the image.

EXAMPLE 3 Light-sensitive material A light-sensitive layer is prepared from a solution of:

30 mg. of dye No. 3, I mg. of 1-phenyl-3-methyl-pyrazolin-5-one, 2.5 g. of ethyl cellulose, and

ml. of ethyl acetate.

The solution is applied to a layer support of glassine paper and dried in the usual manner.

Image-receiving layer The following casting solution is applied to a layer support of baryta paper:

5 g. of 4-dimethylamino benzene diazonium tetratluoborate,

1 g. of saponin, and

1 g. of polyoxyethylene hydroxyethyl cellulose.

Processing The material is processed as described in Example 2. A positive red image of the original on a grey background is obtained.

EXAMPLE 4 Light sensitive material as in Example 1.

Image-receiving material 50 mg. of a leuco cobalt phthabcyanine stearylamine complex prepared by the method described below are dissolved in 40 g. of a 1.5% polyvinyl acetate solution in acetone and 26 g. of a 4% cellulose acetate solution in acetone, cast on paper and dried.

Processing Processing is carried out as described in Example '2. A blue positive of the original is obtained.

T he leuco CoPc used was prepared as follows:

50 g. of a crude product prepared according to Example 1 of German patent specification No. 855,710 were converted into the nitrate by treatment with concentrated nitric acid as described in German patent specification No. 839,939. 16 g. of the dry nitrate were boiled in 50ml. of cleaning petrol with 15 g. of stearylamine for 20 minutes, the mixture was diluted with 750 ml. of cleaning petrol, the resulting solution was filtered at 100 C. and stirred while cold for several hours and the product which crystallised was removed by suction filtration and dried. The resulting product, of which 27 g. were obtained, was dissolved in boiling ethanol, the solution was stirred while cold and the crystalline product obtained was removed by suction filtration and dried. 12 g. of an orange colored substance were obtained. a w

Instead of 1-hydroxy-4-methoxynaphthalene, 50 mg. of l-phenyl-5-methy1-3-pyrazolidone may be used as imageproducing compound with the same result.

EXAMPLE 5 Light-sensitive material as in Example 1.

Image-receiving material An image-receiving material is prepared from:

5 g. of ironflll) chloride, 2 g. of nitrilotriacetic acid, and 30 ml. of a 5% aqueous solution of polyvinyl alcohol.

1 7 EXAMPLE 6 Light-sensitive material as in Example 1.

Image-receiving material 1 g. of bismuth nitrate is shaken in a ball mill for 6 hours with 7 40 g. of a 1.5% solution of polyvinyl acetate in acetone,

and

26 g. of a 4% solution of acetyl cellulose in acetone.

The mixture is cast on paper and dried.

Processing Processing is carried out as described in Example 2. A brown positive is obtained. Instead of bismuth nitrate, 0.6 g. of thallium(1) chloride or 0.8 g. of mercury(II) bromide may be used with equal success in the imagereceiving layer.

EXAMPLE 7 Light-sensitive material as in Example 1. The material is processed as described in Example 2 but the imagereceiving material used is ordinary writing paper. A positive cyan image of the original is obtained.

EXAMPLE 8 Light-sensitive material as in Example 1.

Image-receiving material Ammonia is added to a solution of 5 g. of copper(III) chloride in 75 ml. of H until the precipitate formed redissolves and 30 ml. of aqueous polyvinyl alcohol are then added and the solution is cast on paper and dried.

The material is processed as described in Example 2. A grey-green positive image of the original is obtained.

EXAMPLE 9 When used in combination with other dyes, e.g. erythrosine which is sensitive at 540 nm., the dyes listed in the following table extend the sensitivity of the lightsensitive material to the blue or red region of the spectrum.

Light-sensitive material The following casting solution is applied to a layer Support of polyethylene terephthalate and dried:

30 mg. of erythrosine,

30 mg. of a dye shown in Table 6 below,

50 mg. of l-hydroxy-4-methoxynaphthalene, 2.5 g. of ethyl cellulose, and

150 ml. of ethyl acetate.

Processing A set of interference filters was used to determine the spectral sensitivity of the light-sensitive material. The filters are permeable to the following wavelengths: 350 nm., 390 nm., 405 nm., 435 nm., 480 nm., 505 nm., 515 nm., 540 nm., 550 nm., 570 nm., 590 nm. and 605 nm.

The light-sensitive material is exposed behind the interference filters to a 1000 watt iodine quartz lamp from a distance of 30 cm. for a length of time varying from 5 to 30 minutes according to the dye. The exposed material is brought into contact with the image-receiving layer described in Example 1 and processed in a conventional commercial heat development apparatus.

TABLE 6 Dye Sensitivity at the follow- No. ing wavelengths Erythrosine 18 EXAMPLE 10 Light-sensitive material The following casting solution is applied to a layer support of polyethylene terephthalate and dried:

30 mg. of erythrosine, 30 mg. of a dye shown in Table 7,

50 mg. of l-hydroxy-4-methoxynaphthalene,

2.5 g. of ethyl cellulose, and 150 ml. of ethyl acetate.

TABLE 7 Dye No.2 Steps Vi 7 Erythrosine We claim:

1. In a process for producing copies of a graphic original comprising placing in close contact a first layer of a material containing a sensitizer which renders the layer sensitive in a visible spectral range and an image-producing compound capable of being transferred from the first layer and being characterized as readily forming a nontransferable product upon exposure, with a second receiving layer of a material containing a compound which reacts with transferred image-producing compound to form colored compounds and being characterized as insensitive to the visible spectral range, exposing the first layer to image-forming light in the said spectral range, for a time sufficient to form non-transferable products of said imageforming compounds in exposed areas, heating of the layers in contact with each other at a temperature of between -200" C. to transfer the image-forming compound in the unexposed areas to the second receiving layer, and forming a stable dye by reaction of the transferred imageforming compound and the insensitive compound in the receiving layer, the improvement step wherein the imageforming compound is exposed in the presence of a neutrostyryl dye of the following formula:

wherein R and R may together represent the ring members required to complete an isocyclic or heterocyclic keto methylene ring or they may represent the keto methyl- 19 ene compounds represented by the following structural formulae:

W i A R =hydrogen or nitro;

R ,R ',R =hydrogen, OR S-R or NR R =a saturated or olefinic alkyl group or aryl; Z and Z =hydrogen, alkyl or alkoxycarbonyl, or Z and Z =may represent the methylene groups required for completing a S-membered or 6-membered ring; n=0, 1 or 2; and X=oxygen or sulfur.

2. A process according to claim 1 characterized in that the sensitizers used are neutrostyryl dyes of the N,N- disubstituted thiobarbituric acid series.

3. A process according to claim 1 characterized in that neutrostyryl dyes which contain open or cyclic ether groups are used.

4. A process according to claim 1 characterized in that the following compound is used as sensitizer.

I it I 7 5. A process according to claim 1 characterized in that the following compound is used as sensitizer:

l 0oHi-CooH o N'C2H5 6. A process according to claim 2 characterized in that the following compound is used as sensitizer:

7. A process according to claim 2 characterized in that the following compound is used as sensitizer:

8. A process according to claim 1 characterized in that a l-hydIoxy-4-alkoxynaphthalene is used as image-producing compound.

.9. A process according to claim 8 characterized in that 1-hydroxy-4-methoxynaphthalene is used as image-producing compound.

10. A process according to claim 1 characterized in that 1,2,3,4-tetrahydro-S-hydroxyquinoline is used as imageproducing compound.

11. A process according to claim 1 characterized in that a 3-pyrazolidone derivative is used as image-producing compound.

12. A process according to claim 11 characterized in that 1-phenyl-4-methyl-3-pyrazolidone is used as imageproducing compound.

13. A process according to claim 1 characterized in that a pyrazolin-S-one compound of the following formula:

wherein R =(l) hydrogen, (2) a saturated or olefinically unsaturated aliphatic group, (3) aryl, (4) a heterocyclic group or (5) cycloalkyl;

R =(l) hydrogen, (2) a saturated or olefinically unsaturated aliphatic group, (3) aryl, (4) a heterocyclic group, (5) cycloalkyl, (6) hydroxyl, (7) amino or (8) an alkoxycarbonyl group;

R =(1) hydrogen, (2) a saturated or olefinically unsaturated aliphatic group, (3) aryl, (4) amino or (5) alkoxy;

R =hydrogen or a 4-aminophenylamino group; or

R and R represent the ring members required for completing a carbocyclic or heterocyclic ring,

is used as image-producing compound.

14. The process as claimed in claim 1 wherein the insensitive compound in the second receiving layer is a silver compound.

15. A process according to claim 14 characterized in that an image-receiving layer which contains silver salts of a long chained aliphatic carboxylic acid having 8 to 24 carbon atoms is used.

16. A process according to claim 14 characterized in that an image-receiving layer which contains a silver salt of an aliphatic carboxylic acid which is substituted with a thioether group is used.

17. A process according to claim 1 characterized in that an image-receiving layer which contains a toner is used.

18. A process according to claim 1 characterized in that an image-receiving layer which contains a sterically hindered phenol is used.

19. A process according to claim 1 characterized in that the image-receiving layer contains a white pigment.

20. A process according to claim 1 characterized in that the image-receiving layer contains a terpene resin.

21. A process according to claim 1 characterized in that the image-receiving layer contains a metal ion image intensifier.

22. In a light-sensitive photographic material wherein a light-sensitive layer contains a sensitizer and an imageproducing compound which is transferable at temperatures of between and 200 C., the image-producing compound being converted into a non-transferable reaction product in the exposed areas in the presence of the sensitizer, the improvement which comprises as sensitizer, a neutrostyryl dye of one of the following formulae:

CsHs

R R R =hydrogen, OR SR or NR R =a saturated or olefinic alkyl group or aryl; Z and Z =hydrogen, alkyl or alkoxycarbonyl; or Z and Z may represent the methylene groups required for completing a S-membered or 6-membered ring; n'=0, 1 or 2; and X=oxygen or sulfur.

23. A material according to claim 22 characterized in that it contains, as sensitizers, neutrostyryl dyes of the N,N'-disubstituted thiobarbituric acid series.

24. A material according to claim 22, characterized in that it contains neutrostyryl dyes which contain open or cyclic ether groups.

25. A material according to claim 22 characteried in that it contains the following compound as sensitizer:

26. A material according to claim 22 characterized in that it contains the following compound as sensitizer:

28. A material according to claim 23 characteried in that it contains the following compound as sensitizer:

29. A material according to claim 22 characterized in that it contains a l-hydroxy-4-alkoxynaphthalene as imageproducing compound.

30. A material according to claim 22 characterized in that it contains 1 hydroxy 4 methoxynaphthalene as image-producing compound.

31. A material according to claim 22 characterized in that it contains 1,2,3,4-tetrahydro-8-hydroxyquinoline as image-producing compound.

32. A material according to claim 22 characterized in that it contains a 3-pyrazolidone derivative as image-producing compound.

33. A material according to claim 32 characterized in that it contains 1-phenyl-4-methyl-3-pyrazolidone as image-producing compound.

34. A material according to claim 22 characterized in that it contains, as image-producing compound, a pyrazolin-5-one compound of the following formula:

wherein R =(1) hydrogen, (2) a saturated or olefinically unsaturated aliphatic group, (3) aryl, (4) a heterocyclic group or (5) cycloalkyl;

R 1) hydrogen, (2) a saturated or olefinically unsaturated aliphatic group, (3) aryl, (4) a heterocyclic group, (5) cycloalkyl, (6) hydroxyl, (7) amino or (8) an alkoxycarbonyl group;

R =(1) hydrogen, (2) a saturated or olefinically unsaturated aliphatic group, (3) aryl, (4) amino or (5) alkoxy;

R =hydrogen or a 4aminophenylamino group; or

R and R may also represent the ring members required to complete a carbocyclic or heterocyclic ring.

References Cited UNITED STATES PATENTS 3,180,731 4/1965 Roman etal 9629 3,219,446 11/1965 Berman 9628 NORMAN G. TORCHIN, Primary Examiner I. L. GOODROW, Assistant Examiner U.S. Cl. X.R. 

